Along with recent miniaturization in a semiconductor device, when fine particles that adhere onto a semiconductor wafer are present during a process of manufacturing the semiconductor device, the fine particles cause a problem in manufacturing of the semiconductor device, and thus a method of reducing a dust is required.
Ina plasma chemical vapor deposition (CVD) process, when carrying out film formation without using an oxidation reaction, a process of forming a film onto an object to be processed is carried out in a plasma atmosphere by applying high-frequency power to a material gas, or the material gas and an inert gas. At this time, when the application of the high-frequency voltage is stopped after completion of the film formation process, as a countermeasure for fine particles (dust), the high-frequency voltage is shut off after stopping supply of the material gas. However, an abnormal reaction occurs in the material gas that remains inside a reaction container for an interval between supply stoppage of the material gas and application stoppage of the high-frequency voltage, and thus nano-sized fine particles are generated. When the fine particles are generated, these fine particles are deposited on the semiconductor device, and thus a desired pattern may not be obtained. As a result, a decrease in operation reliability and a decrease in a yield rate are caused. An example of related art includes JP-A-2010-168870.